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Bruce Weaver


Worth noting the work of John Todd
In his book healing earth. Great sail ship ideas!

John Mawhorter


Really like these two quotes:

Andrew Simons: “On the EcoClipper500 there needs to be a manageable compromise between energy use and comfort. Energy use on board will have to be actively managed. Resources are finite, just like for the planet. In many ways the ship is a microcosm of challenges that the wider world has to face and find solutions to.”

Jorne Langelaan: “At sea you are in a different world. It doesn’t matter anymore if you can take a daily shower or not. What matters are the people, the movements of the ship, and the vast wilderness of ocean around you”.

It roughly encapsulates a lot of what I find valuable about this site... thinking in detail about compromises that must be made, rather than assuming that in the future we must have the same levels of comfort when they are unsustainable.

As you note at the end, the speed/volume of a global sail-cargo economy implies the heavy degrowth to a sort of hybrid late 19th-early 20th c. economy style that is probably necessary to reduce emissions enough for civilization/our species to survive.

Thinking carefully about what technologies are worth preserving/reviving like this is very hard work, thanks for all you do!



Any thoughts on incorporating higher altitude kite sails into modern designs?



Excellent article. A key driver for transportation system economics is the number of passenger km or tonne-km that can be delivered per year. This will have a strong effect on unit freight or ticket carriage cost because capital costs must be amortised against revenue. A slower speed is therefore a problem and you are relying upon the money saved in fuel exceeding the higher marginal capital cost and of course, the cost of consumables like food for passengers and crew. For this reason, I think sailboats will be more applicable to freight than passenger transport. The sails themselves will make container transport loading and unloading more difficult.

I would be interested to see an analysis of the potential for hydraulic capsule transportation. This would involve transporting goods at low speed contained within capsules floating within a pipe. The capsules could either be powered individually, or carried along in a moving stream of water, which could be pumped using wind powered pumps. Capsule pipelines could even be laid under the sea, in the way the old communications cables used to be. On land, there would seem to be no reason why goods cannot be transported over entire continents using wind powered capsule pipelines, perhaps 2m in diameter.

Drew Pearce


Great article. It's so important not to let promises of innovation obscure the need for relatively large curtailments of demand.

It's worth noting that 30-40% of international shipping demand (in t.km) comes from moving fossil fuels around. So a successful transition of the global economy away from the use of fossil fuels would likely to lead a fairly large reduction in demand itself. Although that would of course depend on whether any replacements also required significant shipping.

Nancy Sutton


Thanks a million - your work has inspired me for a long time :)

John Somdecerff


Hello Kris,

Thank you for another great article. I sometimes dream of having my own sailing ship.

However, I may have found a mistake.

You wrote:

ten rowing machines operated continually in shifts would provide as much power as the hydrogenerators at a speed of 7.5 knots. If there are 60 people on board, and everybody would generate power for less than one hour per day, no hydrogenerators and batteries would be needed at all.

However, if I'm thinking about this correctly, if there are 60 people for ten machines, each machine gets 6 people.

24 hours/6 persons = 4 hours/person

In addition, perhaps it is because I'm old and mostly sit in front of a computer, but 100 Watts is about all I can put out continuously.

So it seems that every effort must be made to minimize the use of electricity.

Thank you again for another great article,

John Somdecerff

PS I also love your articles about your solar powered web site. On my "to do" list is to post a comment about models of energy efficient cable modems. I've been meaning to upgrade my home service, but somehow I'm always busy with other things....

Jules Baw


Hi, I have followed Low Tech Magazine closely for many year now, its one of my favourite publications and also bought the book!

I am trained in traditional boat carpentry in Sweden, unfortunately there are not so may wooden boats around, so I mostly work with traditional building renovation techniques.

I have been thinking about various methods of propulsion/energy and wind power is the obvious no 1 propulsion method, however as a secondary power/heat source and one of the things I have been wondering about is Woodgas, or more specifically Pyrolysis, or to put it simple. . . making Biochar during the journey.

This would provide a heat source and some of the heat energy could be converted to electricity, though I have no idea how efficient that system would be. It would require large amounts of wood fuel, which may not always be readily available and is taking up cargo space, however upon arriving on destination the ship would have a cargo of Biochar thst does have a value.

Could the kinetic movement of the ship moving up and down somehow be converted into electrical energy? Kind of like those flashlights that share up when they are shaken?

Just some thoughts, that may be interesting to consider.

Thank you for wiring such thorough engaging and interesting articles!

Jules Baw

Jose Amador Silva


Perhaps I am thinking of this technology wrong, but, it occurs to me that all that steel, technology, labor and innovation would be better served building a tunnel and connecting Alaska and Asia.

Then passenger rail, cargo rail, and liquid fuels,.nat. gas, alcohol fuel, etc could be sent across it when needed. The rails could be run on electricity and generated from multiple sources.

I love sailing ships and they do have a place in our world and will continue to have a place, I just don't think we'll somehow rebuild the sailing age again unless civilization degrades, in which case we won't have nearly the same levels of cargo movement or travel.

Nope, rail or tunnels is the way to go, underground and a little more reliable. Other than that... local production from global information sources would be ideal.

 James Campion


Interesting article Kris - although somewhat depressing, as it's difficult to envision large numbers of people being willing to sacrifice the convenience of modern global shipping. There is a Swedish consortium looking into building a sail powered/assisted ship for transatlantic car cargo:


They claim a 90% reduction in emissions, with a max cargo of 7000 cars and sailing time of 12 days. The ship itself is a 200m RORO design with 50 m high retractable sails. A lifetime analysis has been performed by two MSc students at SSPA (one of the partners):




hello Kris,

glad to see an end to end analysis on the carbon intensity needed to build and power a vessel.

i am curious to know if you have ever written / researched on the emission from the moment the boat docks until the good is delivered to the end customer (home or market or retail store)

in the shipping today, efficiency equals big size / large cargo. but delivering the cargo from remote commercial ports is very emission intensive

the sailing vessels you describe are small relative to large bulk / containerships, thus reducing the infrastructure need in the harbor, this is an opportunity to develop a pier to pier trade, smaller vessels, but acceding port cities, delivering goods in the middle of a city, to a large market.

thanks for reading!

best regards

 Sacha Ferbus



Nathan Moore


I believe this post is the equivalent of a real “crowd-pleaser” for us fans of Low Tech Magazine...

 Nick Macedo


In regards to wooden ship building and its environmental impact, the use and consumption of wood does indeed impact local forest environments. With that said, over time, using wood (especially in those quantities) is technically a form of carbon capture assuming the deforestation would eventually regrow. A sapling consumes vastly more c02 over a period of time vs. A fully grown tree no?

Mario Stoltz


Ah, wonderful topic and - as has been pointed out above - also very nice to visualize the change we need as a world society overall if we seriously consider becoming reasonably sustainable.

One item I noticed in the article is that the entire EcoClipper 500 is pictured as static so that the energy / CO2 equivalents can be written off over 50 years. Unfortunately, that won't be the case. The salt mist above oceans is quite corrosive and the constant motion wears many items quickly.
All sails and the many kilometers of running rigging - regardless how modern their material - must be considered as consumables, and will have to be replaced every few years even best case.
Any ship - regardless if made of steel or wood - consumes lots of paint just to maintain the conservation of the surfaces against the elements (as well as tar and hemp to maintain the watertightness of a wooden ship). This also will mean several hundred kilos of these items every year. Also the working time and effort necessary to apply these is not a minor item.
Note that compared to large steel ships, the decks and rigging of sailing ships are much lower to the water and therefore more exposed to corrosion.

All of that is not an argument against sailing ships - rather points out how unsustainable current sea transport is today.

Another difference between sea cargo transport "then" and now is that today, all sorts of goods are transported by sea, including huge volumes of basically worthless plastic trinkets. Back when sailing transport was the norm, only relatively dense, high-value cargo made up what was moved. Lower-value goods were only transported if no other cargo was available, or to fill ships on their way back if they were serving routes with asymmetric commercial conditions (i.e. between a higher-developed country and a place that was mostly an import target).

Richard Kirby


I was lucky enough to do a round the world yacht race 20 odd years ago. We allowed ourselves one shower every 8 days (roughly when it was our turn to be on mother watch).

OTOH we had a massive dome on the back with a satellite dish that we could use for internet access (primarily access to weather information). So we needed to run the generator for several hours each day to keep the batteries topped up.

The hot water for the shower came from either the generator or running the engine (in neutral since we obviously were a sailing race). We had a desalination plant onboard too which needed the generator to run. In theory though our fresh water tanks were large enough to last in an emergency for most of a race leg, and under the race rules we were required to keep at least 2 of the 4 tanks fully topped up, and recommended to keep the other 2 mostly full.

The actual sailing bit was all manual, including hanking on sails, hoisting, and using winches.

Pr. Théodose


As a slight aside, over 100 wooden steamships were built for the U.S. Emergency Fleet at the end of WW1 but didn't see much action during or after the conflict.
They weren't equipped with sails but could still constitute an useful template for a modern wooden cargo freighter.

Steven Woods


Dr. De Decker,

On 11 May 2021, you published an excellent article on building and designing a carbon neutral sailing vessel, which brought up a number of good points about the carbon impact of sailing vessels, and the necessity to adapt our habits and lifeways to a restricted transportation capacity in future if we are to realize a viable climate transition.

While I enjoyed the article, it did fail to touch on two things: First, that we are now in a situation where we must carefully choose what impacts we inflict on the world as we make a transition away from fossil fuels, with Sail Freight being one of the better options for the majority of trade in this case. Second, that trade can only be reduced within certain boundaries. The second point is the most important, and what I would like to address here, as I recently completed my Master’s thesis on the subject.

The major reason shipping, both international, coastal, and inland, cannot be reduced beyond a critical threshold is that cities must receive around 2.5 kilograms of food per capita daily to stay alive. A more realistic figure over the long term would be about 3.4 kilograms per capita daily. Of course, since victory gardens, urban farms, and other plans to grow food in cities simply cannot create the capacity needed to feed a city within its own boundaries, food must be shipped in from elsewhere. Even relatively large areas examined as a system, such as New England, with a greatly expanded agricultural base, will still have to import around 50% of their food in 2060, for 15 million people. This requires shipping capacity, because food on a dock in Australia simply cannot be eaten by people sitting at a table in Providence, Rhode Island.

With this in mind, a fleet which models roughly around the foodshed of New York City’s Metro Area, with a population of 20,000,000 people, requires some 9,589 ships of 111.5 tons Cargo Deadweight Tonnage (CDWT) and a labor pool of some 62,330 sailors. The coffee fleet of New York, if using Belem Brazil as the coffee’s point of origin, adds another 84 ships and 546 sailors. These ships are small vessels, roughly the size and capacity of Avontuur, and as you observed in your article, the larger the ship, the less voyages required for the same level of supply. Thus, what becomes truly important for each major portion of the supply system is Fleet Tonnage, which for New York is total of 1,066,145 at the 2.5 kilogram per capita level of supply. At 3.4 kilograms, the fleet tonnage in this model increases to 1,446,855 tons. New England, with a population of 15 million, would need a fleet capacity of 301,289 tons for external trade only, assuming 50% of the region’s food is produced locally. The internal flows of food would likely require a fleet of similar size along the region’s coastal and inland waters to move food from rural to urban areas. These numbers are absolute minimums, allowing for no crew rest or ship idle time aside from lading and unloading, and the amount of supply is similarly a near absolute minimum.

Sail Freight also helps with the balance of available energy for transporting food to places not accessible by water. By using the wind to transport goods as close as possible to inland cities, and near exclusively for transport to coastal cities, the demand for energy on inland transportation systems such as rail and road is reduced significantly. Due to the comparative lack of available energy from biofuels, renewably generated electric power, and other sources for powering trains and trucks, as well as the basic limitations of electric trucks and trains, when compared to fossil fueled systems, reducing the energy demands of inland transportation should be a top priority at every level.

Another unstated advantage of windjammers is their suitability for a highly democratic form of trade and ownership. Inexpensive wooden, and even steel or fiberglass vessels converted from leisure use or built to the purpose allow small groups, such as a coalition of farmers or a food co-op to establish their own transportation networks free from fossil fuels and most outside inputs. This allows the reduction of middle-men taking farm cuts of food money, and increases the autonomy of communities in decision making and economics, freeing them to some degree from Mumford’s Megamachine and Megatechnics.

Sailing Vessels can be built both rapidly and with very little capital. Additionally, they can be produced without the use of Strategic Materials for either the current Petroleum economic system, or those needed for the transition to renewable energy. Through their lifetime they have very minor emissions compared to electric trucks, container ships, bulk ships, and even trains. The comparative lack of additional infrastructure which would be needed to adopt and proliferate the use of such transportation capacity is also worth considering, as small vessels will be especially well suited to delivering directly to smaller ports, reducing the use of more energy intensive land transportation for the final legs of the food journey. While windjammers are generally a bit slower, they are still one of the best options available to the world for ensuring we don’t have either mass starvation in cities or an absurd overshot of any survivable climate change thresholds.

While this level of food transportation is of course the floor of trade capacity which cannot be reasonably reduced without significant human suffering, a larger windjammer fleet should be encouraged. The movement of Strategic Materials such as Lithium, Cobalt, Manganese, Indium, Silica, Copper, and all the other metals and materials needed to make a socially acceptable and Just energy transition will be critical, and these materials are not distributed justly across the world. Without a low-impact means of transporting these materials, tools, equipment, and resources across the globe, many regions will likely continue using fossil fuels to maintain a socially acceptable level of energy use. While we may understand this is both stupid and suicidal in the long term, most peole don’t seem to understand this yet. Burning tens of thousands of tons of oil to move the tools of a renewable and sustainable future to their points of use seems both absurd and self-defeating; windjammers offer a means of doing so with relative ease and reasonable environmental costs.

In short, when examined at scale, there are few technologies which can both keep cities alive and move the necessary cargo for the energy transition with such low emissions as sail freight. Further, the advantages of a sail freight future for the democratization of trade, energy, transportation, and the economy lend an additional set of reasons for encouraging the proliferation of sailing vessels wherever practical. Essentially, the design of the ship is immaterial, so long as it sails and we change our outlook on trade to moving only hat which is actually necessary.

I have attached my thesis for your review, if you are so inclined.


The appendixes include a directory of current and planned sail freight operations worldwide (pp 94), which may be helpful. Fleet requirements for a variety of US cities and regions are included in the tables throughout, and a rather limited eans of calculating bunker fuel use avoided through sail freight is also provided, though I am in the process of adapting this particular portion of the thesis to a wider variety of vessel types as I expand the thesis into a book-length study.

Thank you for your time and consideration. It should be noted I am a big fan of your work, and used it extensively in researching and writing my thesis. I look forward to more reading on your site, and, of course, I’m always partial to anything sail-freight related.


Steven Woods

Mario Stoltz


@Steven Woods,
thank you so much for sharing your master thesis with all of us, I just downloaded and very much look forward to reading it. While I must admit I struggle to imagine a world with sustainable sea transport on such a scale, I would certainly very much welcome it.
Best wishes.

Alistair Chaplin


Hi. Refering to the contribution of the sails and spars to the carbon emissions associated with a modern windship you may be interested in a paper we did looking to estimate the EROI of a modern windship that we presented at the Innovsail 2020 conference. This may be the envelope you lost...

Frederik Marain


My father (a sailor) used to say: "A sailing ship is the most expensive way to get around in the cheapest way."

Israel Walker


@ Dr. De Decker

Excellent article. It's an unpopular minority opinion to regard green technology as technology with advantages and drawbacks rather than magic.

Some random thoughts your article inspired:

It would seem that the energy use of the ship's crew per capita would need to be compared to the energy use of the ship's crew staying at home. The energy cost of human life must be paid no matter where the lives are.

It seems there is room for significant improvement regarding labor. One wonders at what point it is more effective in energy use to run the ship as a drone with basic autonomous and remote control, but board the ship with full crew for the first and last 1% of travel.

The numbers for steel surprise me, and I wonder if we were going to project a low fossil fuel technology base for steel, how they might change. For instance, recycled steel in Norway (where 95% of power is hydro) using sea algae or wood pulp charcoal rather than coal as the carbon base? In such a case steel becomes a carbon sink, like wood.

There is the further option of biorock/seacrete ships. Concrete ships are well known, and well studied. Biorock and concrete have approximately similar embedded energy. While concrete has high carbon emissions, biorock can be made from any source of electric power, including offshore electric.

For coastal trade, also might consider marine, below-the-surface trolley system using offshore wind power, and inductive transfer at the pantograph, with electric motors on the ships. Offshore wind power needs to be laced together with submarine cable anyway. As long as the cable was hung 25 m below the surface, Malaccamax ships (which have the deepest draft) could safely pass over it. The Asia/India/Suez/Europe trade route can and does stay within the green zone for offshore power. This is still wind power, albeit using late 19th century technology rather than late 18th.

Projecting further into the future, submarines are more efficient (in terms of watts/ton of cargo)than surface ships. Submarine gliders are the most efficient of all, needing to use energy only to change ballast, and gliding 20-35 m forward for every 1 m they sink or raise. In the small sizes already being built they have 1500 km range and 6 month operational lives on pure battery power. Concrete submarines are already tested technology and are ideal for deep water operations.

@ Mr. Steven Woods

To me, a technically minded person with terrible social skills, it seems that dismantling population centers down to a patchwork of six story cities approximately the size of Eixample is no less doable than any of the other changes we must make. It never crossed my mind that the >1M person city was sustainable due to logistical tail lengths.

Feri Setiawan


21st century sail ship must employ
1. Automatic navigation (ship outopilot) wind data from sea drones, buoys and satellites;
2. Stirling engine on parabolic solar concentrator for onboard power and backup propulsion;
3. Selective bulk cargo;
4. Selective route.



Nuclear marine propulsion is a viable technology for implementing long range carbon reduced shipping. Fukushima doesn't reinforce it's danger, it proves its safety. A 40 year old reactor was hit by a massive earthquake & tsunami much larger than design tolerance and survived remarkably well with minimal damage and killed NObody.

The NS Savannah had a near perfect safety record. Ran on a 74 MW reactor with steam plant making 24,000 hp. A smaller reactor and power plant would make a slower vessel, since comparison to wind the power plant, the ship with 8000 hp would yield 7 knots, but do so consecutively around the clock even in dead wind. No batteries.



Ship hulls can be made from ferro concrete.
Examples of WW1 ships built like this are still afloat eg in the harbour of the Island of Scalpay in Scotland.
No need for corrosion protecting paints and approaching infinite hull life.



A ball makes minimal drag on water, what if a large ball was constructed that had a platform inside for cargo but the exterior rotates with the water, cargo capacity with minimal drag? Then a flat top pyramid style frame goes over the ball with sails to provide the propulsion.

I guess im trying to say that the conventional hull is always creating resistance, doesnt a ball shape reduce the drag but still allow load to be carried?




I enjoy reading about low tech solutions to today’s problems. I am interested in novel approaches to shipping cargo.

But less than halfway into reading the article, a ship is referred to as “she”! And then, of course, that absurdity is repeated throughout the rest of the article.

What??? Are you seriously living in the 19th century?? Ships do not have a gender. Ships do not gestate young. They do not lactate. They are not biological beings. They ARE NOT “SHE”!

“She”, to refer to a ship, was ALWAYS done in a sexist way— a male commanded the ship, a male made the ship do his bidding. A male supposedly “cared for” his ship, the way he supposedly cared for “his” woman. There are all kinds of subtle and sexist connotations that men used in referring to their ships, back when women weren’t even allowed on them due to the unimaginable sexism inherent in the society.

Society has changed. Women are fully functioning assets contributing to their societies today. Women command ships today.

Let’s lay off the disgusting, sexist, antiquated language, eh?

In fact, you’d do yourself a service to quickly re-write the article before others also see it. How embarrassing for you.

A woman, not a ship.

John Smith


Quinn: Your comment is a perfect example of the all-to-common absurd "Woke"/PC nonsense about words. You are obviously NOT a sailor and have had nothing to do with ships. I'm a man (a cis man for your information) and I've been sailing yachts all over the world for 60 years. There's nothing sexist about me calling my yachts "she"; its only in your woke mind. If you spend months/years on a yacht it always becomes more than just an "it". I refer to my yacht as a "she" as a term of endearment. All the women captains I've shared my sailing experiences with always referred to their yacht as a "she". Lighten up!!!



I don't remember what they are called, but there are kite-based sails that have been invented to help save fuel for modern ships. It flies in a big figure 8 in front of the ship... and similar kite sails can also be used for power generators (as opposed to electric windmills).



Regarding comments on the use of "sexist" pronoun in the context of ships and projecting the confused reasoning that a human female must literally BE a ship, if any ship is referred to as "she":

It's funny when "woke" ideologues refer to the protection of "MOTHER EARTH" when it comes to environmental stewardship (

Mario Stoltz


@James.Bromfield - I recommend to give this a try in your bathtub, or a pond if you have one available.
A ball indeed has the lowest surface area for a given mass of construction, so it does save material. However by no means does it have the lowest resistance if moving through water. Otherwise there would be way more ball-shaped fish, of which there really is a surprising absence. Also, a ball-(or semisphere-)shaped hull will not serve a sailing ship, which requires clearly anisotropic resistance properties to allow to get to windwards (the resistance must be low in the fore-aft direction, but high in the athwartships direction).

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